As optics designers strive to shrink photonic devices to nanoscale size, they must contend with the fact that diffraction restricts the minimum lateral dimensions of dielectric optical elements and waveguides to about half the effective light wavelength. One solution, according to scientists at Karl Franzens University Graz in Austria, could involve optics based on surface plasmon polaritons. They believe that the polaritons, which are unhindered by the diffraction limit, could provide a foundation for a suitable two-dimensional counterpart of conventional optics.So far, the Graz researchers have developed and tested surface plasmon polariton mirrors, beamsplitters and interferometers -- devices built up from metal nanostructures by electron-beam lithography that can manipulate polaritons propagating along a silver/polymer interface. The report on this work appeared in the Sept. 2 issue of Applied Physics Letters.